ISO 10952:2021

INTERNATIONAL ISO
STANDARD 10952
Fourth edition
Glass-reinforced thermosetting
plastics (GRP) pipes and fittings —
Determination of the resistance to
chemical attack for the inside of a
section in a deflected condition
PROOF/ÉPREUVE
Reference number
ISO 10952:2021(E)
©
ISO 2021

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ISO 10952:2021(E)

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© ISO 2021
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Published in Switzerland
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ISO 10952:2021(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Test liquid . 2
6 Apparatus . 2
6.1 Loading frame . 2
6.2 Dimensional measuring devices . 3
7 Test pieces . 3
7.1 Preparation . 3
7.2 Number . 4
8 Determination of the dimensions of the test piece . 4
8.1 Length . 4
8.2 Mean wall thickness . 4
8.3 Mean diameter . 4
9 Conditioning . 4
10 Test procedure using deflection measurement . 4
11 Test procedure using strain measurement . 6
12 Calculation of extrapolated value . 7
13 Test report . 8
Bibliography . 9
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ISO 10952:2021(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for
the transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications.
This fourth edition cancels and replaces the third edition (ISO 10952:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the tolerances for the dimensional measuring devices in 6.2 have been modified;
— the measurement of the mean wall thickness in 8.2 and the mean diameter in 8.3 have been specified.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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INTERNATIONAL STANDARD ISO 10952:2021(E)
Glass-reinforced thermosetting plastics (GRP) pipes and
fittings — Determination of the resistance to chemical
attack for the inside of a section in a deflected condition
1 Scope
This document specifies a method for determining the chemical resistance properties of glass-
reinforced thermosetting plastics (GRP) pipes and fittings in a deflected condition for nominal sizes
DN 100 and larger.
In conjunction with ISO 10928, this document provides a method for evaluating the effect of a chemical
environment on the interior of a pipe or fitting after a specified period of time. Test conditions and
requirements are specified in the referring International Standard. ISO 23856 references this document.
NOTE It has been found that the effect of chemical environments can be accelerated by strain induced from
deflection; hence, this type of effect is frequently referred to as strain corrosion.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 10928, Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes and fittings —
Methods for regression analysis and their use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
mean diameter
d
m
diameter of the circle corresponding with the middle of the pipe wall cross-section
Note 1 to entry: The mean diameter is given by either of the following formulae:
dd=+e
mi m
dd=−e
mme
where
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ISO 10952:2021(E)

d is the external diameter of the pipe;
e
d is the internal diameter of the pipe;
i
e is the mean wall thickness of the pipe at the bottom.
m
Note 2 to entry: The mean diameter and the dimensions used to calculate it are expressed in millimetres.
3.2
leak failure
failure which becomes apparent by the passage of the test liquid through the pipe wall
Note 1 to entry: Failures of the test sample have been observed at the spring-line location without leakage of the
test liquid. While leakage is not observed, this can be considered a failure of the test sample as the strain levels
in the sample will be altered, invalidating any continuation of the test. The test can be discarded or optionally
counted as a failure occurring at the time of spring-line breakage.
4 Principle
The interior of a test piece is exposed to a corrosive test liquid at a specified temperature while being
maintained in a fixed diametrically deflected condition. The test is repeated at several deflection levels,
using a fresh test piece each time and recording the time to leak failure at each deflection. The results
are used to calculate an extrapolated deflection value for a specified period of time.
Alternatively, the extrapolation can be performed using calculated or measured strains. Strain can be
measured using strain gauges.
NOTE Use of strain allows testing using test pieces of variable thickness and stiffness classes. Deflection and
strain are interrelatable by calculation.
It is assumed that the following test parameters are set by the International Standard making reference
to this International Standard:
a) the composition of the test liquid (see Clause 5);
b) the number and length of test pieces (see Clause 7);
c) the preconditioning to be applied (see Clause 9);
d) the test temperature (see 10.1 or 11.1);
e) if failures do not occur (see 10.11 and 11.11), the specified deflection levels and related minimum
time intervals;
f) the time to which the data shall be extrapolated (see Clause 12).
5 Test liquid
The test liquid shall be as specified in the referring International Standard. The quantity shall be
sufficient to achieve and maintain for the duration of the test the specified depth within the test piece
(see 10.7 or 11.7).
6 Apparatus
6.1 Loading frame
The frame comprises two parallel steel sections and threaded rods which can maintain a constant
deflection of the test piece (see Figure 1 for typical test set-up). The sections shall be sufficiently stiff
such that visible bending or deformation of the sections does not occur during the compression of the
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ISO 10952:2021(E)

test piece. Each section shall have a length equal to the length of the test piece, plus at least 30 mm and
a width of at least 100 mm.
6.2 Dimensional measuring devices
These devices shall determine:
a) the dimensions (length, diameter, and wall thickness) of the test pieces. The devices shall be
calibrated to an accuracy of within ±1,0 %;
b) the change in diameter of the test piece in the vertical direction. The device shall be calibrated to
an accuracy of within ±1,0 %;
c) if used, strain gauges of the foil type, single element suitable for the maximum anticipated strain
level, and a length appropriate for the pipe diameter.
Strain gauges of length 6 mm and 12 mm have been found to be effective for pipe diameters 300 mm
to 600 mm. Consult the strain gauge manufacturer for gauge length recommendations for other pipe
diameters.
Key
1 steel channel section 5 test liquid
2 dam 6 test piece
3 sealant 7 strain gauge (optional)
4 threaded rod D deflected diameter
dm
Figure 1 — Typical test set-up
7 Test pieces
7.1 Preparation
The test piece shall comprise a complete ring cut from the pipe or fitting to be tested. The length of
the test piece shall be as specified in the referring International Standard, with permitted deviations
of ±5 %.
The cut ends shall be smooth and perpendicular to t
...